ITHACA, N.Y. — It will be a seasonably mild but showery week ahead, as multiple storm systems trek across or near Tompkins County in the upcoming days. Your best days for outdoor activity are spaced out – Tuesday, Thursday and Sunday. In other words, you might as well just keep the umbrella by your front door because you’ll probably need it this week.

Your Weekly Weather

Thicker clouds are building in across Upstate New York this afternoon and evening as a low pressure storm system moves northeastward from the Western Great Lakes and into Canada. This is not expected to be a big washout, as it’s not that strong of a system and the rain will be bands of showers rather than one large mass of precipitation. Total rainfall amounts will generally be around or less than one-tenth of an inch. That said, the system will move slowly through the Southern Tier and Finger Lakes, which will result in an extended unsettled period where showers may occur.

For the rest of your Sunday, light rain will be moving in over the next couple of hours, and temperatures will fall back from around 70°F to around 60°F by sunset, that initial batch of rain cooling Tompkins County off from its daytime heating. Overnight there will be mostly cloudy skies and scattered light rain showers through sunrise. With the moisture and cloud cover, lows will be fairly mild, in the low 50s.

Monday will see the cold front with that Canadian slowly crawl through the region. Once again, this is not a strong storm, so it’s not really drawing in a large amount of cold air into its circulation. Expect mostly cloudy skies with some scattered light rain showers, and highs in the mid 60s. The showers will taper off between sunset and midnight Monday night, with mostly cloudy skies, light north winds turning calm, and lows in the upper 40s.

Tuesday is looking a little warmer as southerly flow is enhanced ahead of a developing area of low pressure over the Midwest, which will move quickly eastward into the Ohio River Valley. With light southerly winds, temperatures will make it into the low 70s; partly cloudy skies will become overcast by early evening as the edge of the storm system begins to work into Western and Central New York. A few showers will make it before sunset, but the bulk of the rain will fall Tuesday night, moving in a little after sunset and continuing all night and into the day Wednesday. The core of the low will pass eastward over Pennsylvania Tuesday night, and it will be a rainy night with overcast skies, maybe even a rumble of thunder or two. Lows will be in the mid 50s. New rainfall amounts will be between one-quarter and one-half of an inch.

Wednesday will be a continuation of that steady rain through the morning, with decreasing rain in the afternoon and finally tapering off after sunset as the low moves southeastward. It will be a cloudy, cooler day with highs in the low 60s, with another one-tenth to one-quarter of an inch of rain during the day. Wednesday night will see mostly cloudy skies and drier conditions after midnight with lows in the upper 40s.

Thursday should offer a brief reprieve of high pressure as the next storm system begins to develop over the Mississippi River Valley. Skies will be partly cloudy with highs in the mid 60s. Thursday night will see mostly cloudy skies with lows in the mid 40s.

The forecast models differ on how much rain will make its way into Tompkins County on Friday and Saturday. Of the two most-referenced models, the American GFS model moves the system much more quickly than the European ECMWF model does. At this point, just realize that rain is likely, with some breaks of sun and highs in the mid 60s Friday. Plan for scattered rain showers and mostly cloudy skies Friday night with lows in the low 40s. As for the weekend, showers are likely Saturday with highs in the upper 50s, and drier, sunnier conditions are expected Sunday with highs in the mid 60s.

Graphics courtesy of the NOAA Climate Prediction Center.

Extended Outlook

Looking into the second week of May, the large-scale pattern favors a ridge in the jet stream over the Eastern United States and Mississippi River Valley, and a trough over the Rocky Mountains and Pacific Northwest. This will lead to warmer than normal conditions over the Northeast. The orientation of the ridge suggests moisture from the Gulf of Mexico will be brought into the Central United States rather than the Eastern U.S., and that should favor slightly below-normal precipitation for the analysis period.

Brian Crandall

Brian Crandall reports on housing and development for the Ithaca Voice. He can be reached at bcrandall@ithacavoice.com.